Colman gas furnace wont light

To restart your Colman Tempstar furnace, first make sure the power switch is in the "On" position. Then press and hold the reset button on the furnace for about 10 seconds to reset the system. After resetting, the furnace should start operating normally.

Why does the gas furnace short cycle - YouTube

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When the gas furnace short cycles, and it does not bring the structure up ... have a frazier Johnson furnace with 9 blinks on diagnostic light. just ...

Mobile Home Furnace Troubleshooting - Mobile Home Repair

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Make sure the gas valve is turned to the ON position after you had it in PILOT position. Also check the thermostat low voltage wiring @ furnace...jumper the Red & White wires to bypass the thermostat temporarily. Make sure there is 24 volts on you low voltage circuit.

I had the exact same issue and replaced the control circuit board, igniter, flame sensor, and thermostat just to discover the real problem was a rusted out Roof Jack. (The exhaust pipe that goes through the roof. The inner fresh air pipe was rotted out so the furnace was sucking exhaust gases in which would not support combustion. Have your's checked.

check your high limit switch find blower motor and unplug white wire let furnace run it should shut off when hot enough if same problem replace high limit switch

check air filter is clean and all floor vents are open and not blocked see what room stat is set at this could not be working at the temp you need , furnace might need servicing

thermocouple is bad, thats the little probe that sits in the pilot flame, and runs back to the gas valve

Open up the unit to get to the control board. Make a short jumper wire and disconnect the wires going to R and W terminals on the board. Connect the jumper to R and W. Depress the door safety switch. The circuit board should indicate a call for heat and the furnace should start. If it doesn't, look for a fuse that may have blown either on the circuit board or in the wiring. If the unit started by jumping the W and R but does not when you reconnect the thermostat, you either have a bad thermostat or a bad thermostat wire.

I'm not a furnace technician. But I have worked on several Coleman trailer furnaces. So keep in mind that my terminology might not be exactly correct. But I think I can help you.

I don't know what model you are running, but most of them run pretty much the same. You have a four basic components to check. Thermostat; Ignition Control Module; Pressure Switch; and which ever of the following that you have (Glow plug, Electronic ignition, Pilot Light).

I'm assuming that you are referring to the blower as the "Rat wheel blower" (round wheel looking thing with fins on it). If my assumption is correct and if the power from the breaker box to the furnace junction box (Probably with a on and off switch on top or side), than when you give it power (from breaker box and turn thermostat up) the fan (not blower) comes on. If it doesn't there is a probably a problem with your Thermostat or Ignition Module. If it does come on and your glow plug or you igniter tries to work. Than yes, you are correct, you have to have gas pressure to let the pressure switch know that there is adequate gas supply pressure (gas- 5 to 7 W.C, propane 11 to 13 W.C). The reason for this is if the Pressure Switch doesn't feel the correct pressure. It thinks you have a leak and won't release gas for ignition. After you turn the gas on. If the furnace doesn't ignite. Make sure the Thermostat is definitely wired properly. Now we are down to one of three problems. If the Glow Plug, Electronic Ignition, or pilot light are working properly. Than we are down one of two problems. The Ignition Module or Pressure Switch. Check pressure on the Pressure Switch. If yuou don't smell gas it is probably OK. But it is best if you use a manometer. I have rarely found Pressure Switches bad. Normally if I get to that step. It is the Ignition Module. The Ignition Module kind of like the brain of the furnace. It is located behind one of your front panels. It will have approximately 10 wires going to it. Some will be going to the Thermostat, some to the Glow plug (Igniter), some to the Pressure Switch, and some going to the blower.

I have probably said more than you need to know. If I did I apologize. But to wrap it up. You were probably correct. You definitely need gas for the blower to kick on. The furnace has to light and heat up before the blower will Start. Not to keep rattling, but to check to see if the blower motor will run. Is to switch the Thermostat from "auto" to "run".

Good Luck

look on your burner control relay - look for terminals marked T and TH.  connect up a honeywell thermostat here.